This invention relates to a composition and associated method for treatment of certain ophthalmic conditions. The invention also relates to a composition and associated method for treatment of a number of disease states via an ophthalmic delivery process. The invention further relates to a composition for use as a delivery vehicle or carrier in the manufacture of a composition containing a pharmaceutical substance or therapeutic agent.
Dry eye syndrome is characterized by sensations of dryness, burning, and a sandiness or grittiness that can worsen during the day. Symptoms are typically described as burning, itchy, scratchy, stingy or tired eyes. Other symptoms include pain, redness, a pulling sensation, and pressure behind the eye. The damage to the eye surface resulting from dry eye increases discomfort and sensitivity to bright light and both eyes usually are affected, but symptoms may be occur asymmetrically.
Having dry eyes for a prolonged period of time can lead to tiny abrasions on the surface of the eyes. In advanced cases, the epithelium undergoes pathologic changes, namely squamous metaplasia and loss of goblet cells sometimes due to activation of T cells directed. Some severe cases result in thickening of the corneal surface, corneal erosion, punctate keratopathy, epithelial defects, corneal ulceration, corneal neovascularization, corneal scarring, corneal thinning, and even corneal perforation. An abnormality of any one of the three layers of tears which produces an unstable tear film, may result in symptoms of keratitis sicca.
Another significant benefit of this invention is to provide a preservative-free vehicle for ophthalmic medications. With such chronic conditions as glaucoma, allergies, uveitis, and dry eye and with other frequent needs, the use of ophthalmic medications containing preservatives is counter-productive as they often produce serious side effects to the eye and adnexal structures and accordingly should to be stopped. The preservatives being surfactants damage the epithelium with each use in an infected or already allergic conjunctiva thus reducing the full effectiveness of the desired therapy. Therefore this invention affords significant benefit on 2 major venues, namely, it eliminates the deleterious effects of preservatives, and by its inherent therapeutic antioxidant and emollient properties supplements the therapeutic goal. Another benefit of the present invention is that the medications can be delivered in a single daily dose at night, easily in a dropper bottle form that patients find convenient and economical in lieu of the single-use plastic dropperettes that can scratch the corneas.
There is a need for an improved method and composition for the treatment of chronic ophthalmic conditions such as dry eye (DED) and glaucoma. Conventional treatments require frequent use of eye drops instilled into the eye. There is a high level of interest in using food oils, such as olive oil, in ocular formulas for dry eye treatment or other chronic ophthalmic diseases. Compositions have been proposed which include castor oil to facilitate spreading of the composition over the surface of the eye. See, e.g., U.S. Patent Application Publication No. 2008/0070834 and U.S. Pat. No. 8,679,554.
The great majority of the compositions used include either a preservative such as polysorbate 80 (U.S. Pat. No. 8,679,554), benzalconium chloride or thimerosal and/or an emulsifier or surfactant (Publication No. 2008/0070834). The preservatives and emulsifiers are either toxic to the epithilial cells or are allergenic to the patients. Over time this mild toxicity when induced 2-3 times a day can create serious redness, tissue changes such as conjunctival contracture or subconjunctival fibrosis, and actual damage to already compromised tissue. Thus any method of drug delivery which does not contain these preservatives would be much preferred and would be ready substitutes for present vehicles for eye drug delivery or have inherent emollient benefits as well.